W211 AirCon only working on Passenger Side

[rsb]

I've just driven my W211 E350 (56 plate) back home and put the aircon on but it only seems to be cold on the passenger side, the drivers side is blowing "normal", non cooled air.

I've got the 4 zone climate and turned the drivers side down to low but it was still blowing "normal" air.

I guess a sensor might have gone on the drivers side, giving the aircon a false reading?

Any ideas?

Cheers for now

Russell

 

[Trickythemerc]

Sounds like the DUO valve has failed, a fairly simple job to replace if you are fairly handy.

 

[AMGeed]

Sounds like the DUO valve has failed, a fairly simple job to replace if you are fairly handy.

Looked a pig of a job when I watched my indy do mine. What was worse, the new valve fitted was faulty and they had to do it all over again.

 

[rsb]

I've taken the car to a local Indy and they've checked the AirCon with Star and can find no obvious problems, so are going to replace the Duo valve....fingers crossed that will resolve the problem....watch this space....

 

[tonykirt72]

I had that on my previous volvo and turned out to be low on gas

 

[Stratman]

The way the systems are arranged may be different, but my W203 had cold air from only the left side vents, accompanied by a faint whistle. I took it to be regassed which cured the problem, apparently caused by the direction in which the refrigerant flows. it enters the evaporator on the passenger side and flows across to the driver. There was so little gas in it that by the time it reached the driver's side it had already absorbed all the heat it could and thus didn't do any cooling.

I've noticed a slight drop in cooling from the driver's side vents recently...

 

[rsb]

Just had bad news from the Indy, the new Duo valve hasn't solved the problem, they're now saying that it might be the blend motors but that's a £300 job just to get to so I'm going to have to live with the cool air on the passenger side for now.

I did ask if it could be due to low aircon gas but they assured me that it wouldn't be blowing cool air on the passenger side if that was the case.....although some posts suggest this might be the problem?

 

[Geez1000]

I had the same on my 57 plate S211. Cool on the passenger side and warm on the drivers side. The air con specialist said it could be the blender unit or low gas. The car was re gassed and the car was perfect, cold both sides, turned out when it was re gassed a couple of years earlier, they did not put enough gas in.

 

[Tuercas viejas]

Just had bad news from the Indy, the new Duo valve hasn't solved the problem, they're now saying that it might be the blend motors but that's a £300 job just to get to so I'm going to have to live with the cool air on the passenger side for now.

I did ask if it could be due to low aircon gas but they assured me that it wouldn't be blowing cool air on the passenger side if that was the case.....although some posts suggest this might be the problem?

Yes yes and yes---she said!
The first thing i do in these cases is draw it down, weigh it and recharge with the correct amount of refrigerant! Then conduct a full performance test. Remember the system, any system, even the best systems, lose about 5% of charge per annum.
MB are notorious for this symptom and often the customer gets overcharged for work that doesn't need to be done .
Don't forget new charge valves each and every time its serviced!
Cheers
Tuercas Viejas

 

[millo777]

You can actually use the climate control units onboard diagnostic to check the refrigerant pressure among other useful stuff.


https://www.youtube.com/watch?v=-DQgJddsRlw

 

[Tuercas viejas]

Good indication of course! But that cannot tell you the actual charge and cannot do a full performance test doing temperature loadings . It cannot do a refrigerant condition nor measure if there is the correct amount oil in the system which by the way affects the A/C efficiency.
It cannot do a physical check on the exterior condition of the condenser nor the evaporator. all very important for heat transfer and pumping losses.
That is still for qualified 'umans to do!
Cheers
Tuercas Viejas

 

[rsb]

Thanks for all the suggestions guys, sounds like I need to get to a good aircon specialist ASAP and see if a re-gas resolves the problem.....fingers crossed and watch this space.....

 

[Azeem]

Last year I had similar issue on my w211. After reading forums I also ended up purchasing duo-valve but did not replace it.

The AC diagnostics were pointing to a evaporator (based on the readings from diagnostics).

After researching a little more I put some more refrigerant in the system but it did not resolve the issue.

I wasn't driving the car much since my work place is just a couple of kms from home.

A friend suggested to give the car a good run at highway speeds with AC. After a good run of +200km the AC has been working flawlessly since then.

Hope this helps.

 

[rsb]

Thanks for that, I'm scheduled for a motorway run of about 110 miles each way next week so I'll make sure the AC is on all the time to see if it "kicks in".

 

[rsb]

Good news, I've just driven back from a local garage who have just completed an AirCon service and the systems is blowing very cold air on both sides.

Carl at Stanbridge said that there was only 190gm of refrigerant in the system and there should be 950gm. Apparently there was also a lot of condensation extracted!

Fingers crossed that's resolved the problem with no need for any more expensive work from the Indy.

Thanks for everyone's input, much appreciated.

Russell

 

[Stratman]

Just had mine regassed this morning and there's a vast improvement. Icy blasts from both sides of the car.